Re: [PATCH 1/2] fdt: Allow stacked overlays phandle references

[Frank Rowand <frowand.list-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On 07/03/17 05:41, Pantelis Antoniou wrote:
> Hi David,
> 
> On Mon, 2017-07-03 at 19:06 +1000, David Gibson wrote:
>> On Wed, Jun 14, 2017 at 05:52:25PM +0300, Pantelis Antoniou wrote:
>>> This patch enables an overlay to refer to a previous overlay's
>>> labels by performing a merge of symbol information at application
>>> time.
>>
>> This seems to be doing things the hard way.
>>
> 
> It is the minimal implementation to get things to work, with the current
> overlay implementation. I do have plans for a version 2 with fixes to
> a number of areas.
>  
>> You're essentially extending the semantics of overlay application to
>> add the symbol merging.  You've implemented these extended semantics
>> in libfdt, which is all very well, but that's not the only overlay
>> application implementation.
>>
>>
> 
> This is a port of the same patch that's against the linux kernel.
> As far as I know there's no other implementations, or at least none
> that are open source.

That patch never made it into the kernel.  I submitted a different
patch last week (now at v2, probably soon to be v3, then probably
v4 when 4.13-rc1 comes out), so hopefully we will get the overlay
symbol loading support into the kernel soon.


>> It seems to me a better approach would be to change dtc's -@
>> implementation, so that in /plugin/ mode instead of making a global
>> __symbols__ node, it puts it into the individual fragments.  That way
>> the existing overlay application semantics will update the __symbols__
>> node.
>>
> 
> A lot of things can be made better, on the next version. These are
> minimally intrusive patches to address user requests for the current
> implementation.
> 
> Why don't we start by making a list, and work towards that goal?
> 
> Care to start about what you want addressed and how?
> 
> Regards
> 
> -- Pantelis
> 
>